Manufacture of tetra-ethyl lead



Patented on. 11, 1927,

UNITED STATES:

HERBERT W. DAUDT, 0F PENN S GROVE, ALFRED E. PARMELEE, OE CARNEYS POINT,

PATENT OFFICE.

.AND WILLIAM S. C ALCOTT, 0F PENNS GROVE, NEW JERSEY, ASSIGNORS '10 E. I. DU PON'I. DE NEMOURS &, COMPANY, OF WILMINGTON, DELAWARE, A. CORPORATION OF DELAWARE.

No Drawing.

This invention pertainsv to an improvement in the manufacture of tetra-ethyl lead by the interaction of lead-sodium alloy with 'eth l chloride. Specifically it relates to the ad ition of certain dispersing substances to the mass or sludge resulting from the said reaction, whereby a change in physical condition of the mass is eilected which greatly facilitates its handling and the separation of the tetra-ethyl lead therefrom by distillation.

Heretofore, the nature of the mass has made handling and satisfactory separation very difficult, For instance, in the preparation of tetra-ethyl lead by the interaction of mono-lead-sodiurn alloy and ethyl chloride, the lead sodium alloy is commonly placed in an autoclave with liquid ethyl chloride where the temperature is maintained, generally, between 30 and 60 6, until completion of the reaction. The resulting mass consists of a lead-containing sludge in. which the particles of lead tend to cohere and, by forming balls and sheets, render edective agitation impractical or impossible,

We have found that, u on the addition of our dispersing agents subsequcntl to the completion oi"- the described reaction, the physical condition of the solid material is so changed that it is adapted for ready agitation, and may be handled with relative ease. By reason of the improved condition of the mass,-the tetra-ethyl lead may he efi caciously separated by steam distillation while the mass is undergoing agitation. The

changed condition appears to be due to the I formation of a'film or coating on the surface of the solid material, which film functions to (prevent agglomeration oi the metallic lea It is to be understood, however, that this theory is advanced merely as a probable explanation of the action of the dispersing agents, and that our invention is independent of the correctness thereof.

The desired change in physical condition may be brought about by either an agent exerting a purely physical effect, such as would result from the presence of a protective colloid", or from the absorption of an oil or solvent by the solid mass, or it may be brought about by a substance which unnornornnn or rerun-Erma, LEAD.

i am filed November 2, 1925. Serial No. sense any metal iormin soluble salts and H any acid radical whic forms insoluble lead salts. Examples of salts having the formula and suitable for use 1n the process are sodium sulfide, sodium carbonate and sodi- 7 use sulfate, or salts,

order set iorth our invention detail, the following typical examples oi actual the corresponding potassium embodiments thereof are furnished. It h to understood, of course, that such are amples are purely illustrative.

Example A (action apparently pawl/3,1 ebra I deal),

1 part or" lead mono sodium alloy is placed in an autoclave and the temperature raised to 40 6. To this is slowly added in the space of two hours 125% 01? the theoretical amount of ethyl chloride required for the conversion of the lead sodium alloy to tetrw ethyl lead, After all the ethyl chloride has been added, the charge is warmed for three hours to 60 and then cooled to 25 C After the charge is thoroughly cool any pressure is released and the charge is drowned in water to which has been added en. "no all equal in weight to 3-10% of the tote weight of lead in the charge. The tetra-ethyl lead is removed by steam distillation from the agitated mess.

Example B (a chemical change ire/valved};

In the manufacture of tetra-alkyl lead in the interaction of lead sodium allo wit ethyl chloride, lead sodium alloy an eth l chloride are allowed to react as stated in fill) drowned in water to which has been added sodium sulfite crystals equal in weight to five percent of the total lead present inthe charge. The tetra-ethyl lead is separated by steam distillation from the agitated mass.

Example (7.

The two types of dispersing compounds classified above respectively as reacting chemically and physically,'may be used together, as in the example followin In the manufacture of tetra-alkyd lead by the interaction of lead sodium alloy and ethyl chloride, lead sodium alloy and ethyl chloride are allowed to react as statedm Example A. The reaction mass is then drowned in water to which has been added sodium sulfite e ual to three to ten percent of the weight oi lead and engine oil to the extent of five percent of the weight of lead. The lead tetra-ethyl is recovered by steam distillation of the agitated mass.

When the dispersing agents are employed as directed and exem lified, the cohesion of the lead articles wit attendant formation of lar e alls and sheets is largely prevented, with the result that the mass 1s much more finely divided. By reason of this fact the tendency of appreciable quantities of the lead. tetra-ethyl to remain occluded in the mass is largely overcome. The finely divided mass also, as has been pointed out, may be readily agitated during the distillation, and the thoroughness of the separation very 4 materially augmented.

We claim:

1. In the manufacture of tetra-ethyl lead by the interaction of ethyl chloride and mono-sodium-lead, the improvement which comprises adding to the reaction mass, subsequently to the completion of the reaction, a dispersing substance adapted to' form a 7 ,water insoluble film on the surface of the particles of said mass.

2. In the manufacture of tetra-eth 1 lead by the interaction of ethyl chloririb and mono-sodium-lead, the improvement which comprises adding to the reactionmass, subsequently to the completion of the reaction, a substance adapted to substantially preclude cohesion o the lead particles present therein.

3. In the manufacture of tetra-eth 1 lead by the interaction of ethyl chlori e and mono-sodium-lead, the improvement which comprises adding to the reaction mass, subsequently to the completion of the reaction, a dispersing substance adapted to render said mass susceptible of agitation during steam distillation.

4. The process of manufacturing tetraethyl lead which comprises efiectin action between mono-sodium-lead an chloride and drowning the resulting a reethyl .sequently to the com massethyl lcad which comprises effecting a re- 7 action between'mono-sodiumdead and ethyl chloride, drowning the resulting mass in a liquid containing a substance adapted to preclude cohesion of the lead particles present in the mass, and distilling ofii the tetra-ethyl lead while agitating. I

6. In the manufacture of tetra-ethyl lead by the interaction of ethyl chloride and mono-sodium-lead, the improvement which comprises adding to the reaction mass, sub

an inert substance. :1 preclude cohesion of the lead particles present therein by physical effect.

7. The process of manufacturing tetraethyl lead which comprises effecting a reaction between mono-sodium-lead and ethyl chloride and drowning the resulting mass in a liquid containing an inert oil in sulficient quantity to preclude cohesion ofthe lead particles present in the mass.

8. The process of manufacturing tetraethyl lead which comprises effecting a re action between mono-sodium-lead and ethyl chloride and drowning the resulting mass in a liquid containing engine oil in an amount equal in weight to from 3 to 10% of the total weight of lead present.

9, The process of manufacturing tetraethyl lead whichcomprises efiecting a re action between mono-sodium-lead and eth l chloride and drowning the resulting mass 1n a liquid comprising a mixture of substances adapted to function to preclude cohesion of the lead particles functioning by physical effect, and another functioning by chemical action. I

10. The process of manufacturing tetraethyl lead which comprises effecting a reaction between mono-sodium-lead and eth l chloride and drowning the resultin mass m a liquid comprising engine oil an sodium sulfite.

11. The process of manufacturing tetraethyl lead which comprises effecting a reactlon between mono-sodiuIn-lead and ethyl chloride and drowning the resultin mass in a liquid comprising engine oilv an sodium sulfite, both said oil and said sulfite being present in amounts ranging over 3% of the total weight of lead in the mass.

12. A sludge comprising the products resultin from the interaction of mono-sodiumead and ethyl chloride, together with a dispersing agent.

13. A sludge comprising the products resulting from the interaction of, mono-sodium-lead and ethyl chloride, together with an inert dispersing-agent.

letion of the reaction, apted to substantially- 

